Climate-smart crops get to the root of the problem

New climate-hardy beans that produce good yields in drought conditions and poor soils go, quite literally, to the root of the problem.

The new bean lines developed by CIAT and its partners are resistant to aluminium toxicity and drought, two major causes of crop failure in acid soils during times of low rainfall. Aluminum toxicity causes the stunting of crop roots, preventing them from reaching residual moisture deep in the soil.

Soil acidity and the associated aluminium toxicity affects over 40 per cent of potentially arable areas in the tropics. CIAT plant nutritionist and project leader Idupulupati Rao, explains: “Soil acidity causes aluminium in the soil to become soluble and more toxic to plants. It makes the roots of many important food and pasture crops grow shorter and thicker – this means they’re unable to access residual water deep in the soil.

“In times of low rainfall or drought, there is a strong chance that these crops will fail. But the irony is that even in times of drought, there is often enough water available deep down in the sub-soil to sustain the crops and enable good yields”.

“CIAT has already developed drought tolerant beans that were released in Nicaragua and Rwanda,” he continues. “But by combining this trait with resistance to aluminium as well, we’re producing crops that can tolerate multiple environmental stresses, many of which are found in smallholder farms across Africa, Latin America and Asia.

“These are exactly the scenarios we need to be prepared for as climate change brings more unpredictable rainfall and increasing incidence of drought.”

The research forms part of the Fighting drought and aluminium toxicity (download factsheet PDF) project, funded by the German government (BMZ-GTZ), which focuses on improving the resilience of common beans and the brachiaria forage grasses.

Brachiaria is one of the few crops with a very high level of resistance to aluminium, but only a small number of improved varieties, for example, the commercially-available Mulato and Mulato II, can perform well under drought conditions. CIAT and its partners are using traditional plant breeding techniques to develop new brachiaria hybrids that combine aluminium resistance and drought tolerance, with the ability to perform well in low fertility acid soils.

“It’s an excellent example of the global reach of CIAT,” continues Rao. ” We’re combining our expertise in Latin America, with that of our partners in Africa to develop crops that can benefit small farmers across the Tropics.”